1. Field of the Invention
The present invention relates to a plastic laminated metallic foil and more particularly to a plastic laminated metallic foil, which exhibits excellent properties as a covering material and specifically, electrostatic shielding layer and moisture proofing layer for communication cable. A method for producing these foils is also an integral part of the present invention.
2. Description of the Prior Art
In recent years, covering materials of the shielding type having favorable moisture proofness have been highly desired. In one instance, there is a shielded piece obtained by covering one surface of a metallic foil with a polyolefin as disclosed in Japanese Patent Publication No. 14350/1965 (now abandoned).
According to the invention of that patent publication, since the shielded piece is bonded to a jacket, when the cable is stretched or bent, the metallic foil and jacket are hardly broken. However, since shielded piece possesses but one layer of polyolefin, it is difficult to firmly bond the polyolefin layer to both of the metallic foil and the jacket. As a result, when employing a polyolefin which adheres favorably with the metallic foil, the jacket is extremely difficult to bond to the polyolefin. On the other hand, when employing material other than a polyolefin which adheres favorably with the jacket, the metallic foil remains difficult to bond to the material.
Hence, satisfactory covering materials for communication cable leave much to be desired.